class Foo:
    def bar(self):
        print("Bar")

    def hello(self):
        print('I am %s' % self.a)

    def __init__(self, a, b):
        self.a = a
        self.b = b


obj = Foo('chengd', 18)
obj.bar()
obj.hello()

obj2 = Foo('leonard', 99)

if __name__ == '__main__':
    print('this is main:', __name__)
